re PR fortran/45435 (Automatically generate C interop interface blocks from C code)

re PR fortran/45435 (Automatically generate C interop interface blocks from C code)

2017-08-01  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/45435
	* lang.opt (fc-prototypes): Add option.
	* gfortran.h (gfc_typespec): Add interop_kind to struct.
	(gfc_dump_c_prototypes): Add prototype.
	* decl.c (gfc_match_kind_spec): Copy symbol used for kind to typespec.
	* parse.c (gfc_parse_file): Call gfc_dump_prototypes.
	* dump-parse-tree.c (gfc_dump_c_prototypes): New function.
	(type_return): New enum.
	(get_c_type_name): New function.
	(write_decl): New function.
	(write_type): New function.
	(write_variable): New function.
	(write_proc): New function.
	(write_interop_decl): New function.
	* invoke.texi: Document -fc-prototypes.

From-SVN: r250791